Ive been pulled 3 times in 1.5 years.
Only once has the pull been for anything worthy though. It was around Christmas time, and they pulled me and did a random breathalizer and insurance/car ownership check etc....
The other two times I have been pulled, I have just been asked what I am doing, where I am going and what my name is....... The mind boggles lol!
To be honest on all occasions the police have been quite fair with me, indeed, whilst I was awaiting the results of the checks on my car when I was pulled in a random check, the copper had a pleasent chat with me about me GPS system etc lol! Although it didnt look too good when he found my gf's and her mates empty bottles of booze in the back seats lol!
I think if you are pleasent and upfront with them and you dont look dodgy, or inadvertently make yourself look dodgy, then you should not really have any problems with them.
Having said that though, you can get some really narky coppers, to whom the power has gone to their head lol!
Mind you I might be a bit biased, my grandad was a copper for 31 years, my uncle (his son) was then a copper for 28 years (including 12 years as a traffic sergant), my cousin (his son lol) is a copper who has currently been serving for 5 years and I myself am hoping to join the police one day (in fact I have my initial interview with them for their August intake a week tomorrow!).
Just my 2 pence